Fluid inclusion geochemistry of the Granisle and Bell porphyry copper deposits, British Columbia

摘要: The Granisle and Bell porphyry copper deposits, in north central British Columbia, share numerous similarities but differ that ore at is associated with potassic alteration, whereas an overprint of sericitic alteration. Fluid inclusions the deposits can be classified as a vapor-rich type A liquid-rich types B(liquid + vapor); C(liquid vapor halite); D(liquid halite sylvite); E(liquid K-Fe-Cl phase); F(liquid sylvite G(liquid least one unidentified phase). Type constitute between 25 90 percent relatively constant 70 Bell. Of inclusions, D F dominate C E B are rare both deposits. About homogenize by disappearance; dominant exhibit bimodal distribution homogenization temperatures maxima 500 degrees 900 C. 75 disappearance after vapor, homogenizing largely 400 600 Types fall along same linear compositional trend NaCl-KCl-H 2 O system regardless their temperature or conditions homogenization.Our interpretation these observations context phase equilibria Na/K/Ca geothermometer indicates that:1. Potassic alteration formed ranging from to possibly 800 solutions salinities up K/Na atomic ratios over 0.2. These were probably derived directly magma changed composition crystallization not boiling mixing meteoric water.2. Sericitic 0.2 less similar those Granisle. resulted equilibration water host intrusions about enhancement salinity boiling.3. Most took place during periods high pressure occurred lowered pressure.Comparison our results fluid inclusion data on other suggests containing undisturbed zones phyllic overprints